The longest running experiments

The longest running experiments

What is possibly the world’s longest running science experiment was set up at the University of Queensland, Australia in 1927. The experimental apparatus consists of a quantity of pitch in a glass funnel which scientists monitor to study the flow of the viscous material and the process of drop formation. It takes between 7 and 13 years for a drop to form, but only a tenth of a second for the fluid to fall. The ninth drop fell in 2014 and it is possible to join the watch for the tenth via a webcam at: thetenthwatch.com

• In 1840, the Reverend Robert Walker set up a bell connected to a dry pile (a type of battery) in the entrance to the Clarendon Laboratory at the University of Oxford – the bell has been ringing continuously ever since. The bell’s clapper oscillates at a frequency of about 2 Hz and draws 1 nA from the cell.

• A clock that rivals the Clarendon bell for its longevity can be found in the foyer of the physics department at the University of Otago in Dunedin, New Zealand. The Beverly clock has, in principle, not needed winding since its manufacture in 1864 because it is driven by ambient fluctuations in air temperature which cause an airtight metal box to expand and contract.

• The Science Museum in London houses ‘The Clock of the Long Now’, a timepiece designed to display the correct time for 10,000 years.

• A light bulb at a fire station in Livermore, California has been in nearly continuous operation for a hundred years. The bulb’s luminosity has decreased over its life: it was initially rated at 60 W but now has an output of only 4 W.